This disclosure relates to an airfoil for a gas turbine engine. In particular, the disclosure relates to a cooling enhancement feature for an interior cooling passage of the airfoil and a method of making the same.
Gas turbine engine turbine airfoils typically include complex cooling passages. The cooling passages often include features to increase heat transfer between the airfoil and the cooling fluid flowing through the cooling passage. One cooling enhancement technique has been to provide very small linear grooves adjoining one another. These grooves provide a contiguous ridge that typically extends in a radial direction and increase the surface area of an interior cooling surface.
Another cooling enhancement technique has been to provide pins that extend between and join opposing walls of the cooling passage, creating turbulence in the cooling passage. These pins significantly obstruct the cooling flow and do not necessarily increase heat transfer significantly on an exterior airfoil wall.
Yet another cooling enhancement technique is to provide micro-depressions in the interior cooling surface of the airfoil. This is achieved by milling or electrodischarge machining correspondingly shaped pins on the airfoil core, which is very costly.